Carge Mobile Application

A mobile application for trading used electric cars in Ireland
Project Type
User Interface Design, Mobile Application
Project role
User Research, Interaction Design, Prototyping
Project year


The automotive industry has been pushing increasingly towards cleaner vehicles in recent years, with most major car manufacturers entering this untapped market. Several European nations are also seeking the electrification of transportation because they are concerned about the escalating impact of the transportation industry on global warming, fossil fuel depletion, and urban air pollution. Essentially, the idea is to create a user-friendly and intuitive application for buying and selling electric vehicles. The original idea revolved around creating an app that extended to all car segments. Nevertheless, after further brainstorming and ideation, decided to focus on electric cars.


Currently, It is also significant that no apps are available for the used electric car segment. The main purpose of this app would be to streamline the process of buying and selling used electric cars in Ireland. In terms of design, the app would attempt to address typical usability issues users encounter when using similar applications. Similar applications were analysed and used this information to help make design. The target audience for this app would be the general public interested in buying and selling used electric cars. Signing up as a seller or buyer, searching for cars or vice versa, depending on the type of user, would be some of the main functions. The idea is to keep the visual design of the app simple and minimal yet engaging and intuitive for the users. 

Background Research

Research was initially conducted to identify current trends and identify a niche market within the used car industry. The survey was administered using since it was simple to set up and conduct. Questions were framed either as affirmatives or negatives, with one question based on the Likert scale. To comply with GDPR regulations, the data was anonymised at source, and responses were framed in a way that no participant could be identified from their responses.

Survey and Swot Analysis

A total of 70 participants participated, and a SWOT analysis has been done using these outcomes as a basis for evaluating the viability and commercialisation of the project. The results of this analysis indicate that one identified threat and some weaknesses exist in the project proposal. Nonetheless, considering these factors, the project proposal appears to have more strengths than weaknesses. In Ireland, studies in the field of electric vehicles show that the number of registered electric vehicles is steadily rising. As reported by Sustainable Energy Authority of Ireland, the number of fully electric vehicles has increased substantially from less than 1,000 in 2015 to 17,000 by August 2020. Together with the results of the survey, these stats provided convincing information, and for that reason the next step in the application design process was decided to proceed.

Usability Test Analysis

•  User-Interface Design Guidelines for Visibility: In terms of user-interface design, the most basic rule is to give appropriate feedback to the user. The purpose of this is to keep users informed of the current situation and to facilitate a smooth interaction without wasting time or effort.

•  System to real-world match: Rather than using system-oriented terms, systems should speak the language of the users with familiar words, phrases, and concepts. User interfaces that follow real-world conventions and arrange information in a logical and natural order show empathy and acknowledgement for users.

•  Freedom of Choice: Users frequently make mistakes or change their minds. Give them the ability to exit a flow or undo their last action. It is important to cultivate users' sense of control over the user interface (UI) they are using. Correcting mistakes or reversing choices should be easy for users.

•  Norms and consistency: Different words, situations, or actions should not be interpreted differently. Advocating for consistency and standards may seem like we’re pushing for all applications to look and act the same, but that’s not the case. Standards allow users to know what to expect when they are on a website or using an application, and they increase learnability, improving user experience.

•  Preventing unconscious errors: Avoid unconscious mistakes by offering suggestions, utilising constraints, and being flexible to prevent users from being distracted from their task at hand. Often, it is not a good idea to limit users' choices. However, when there are clear rules that define acceptable options, it may be a good strategy to constrain the types of input users can make.

•  Recall and memory-recognition in user interfaces: A user's ability to recall information from memory is increased when they can see items they recognize instead of needing to recall items from scratch.

•  Flexible and efficient interactivity: Shortcuts - unseen by novice users - speed up the interaction for the expert users, so that the system becomes accessible to both experienced and inexperienced users.

•  Aesthetics and minimalism: Interfaces shouldn't be cluttered with unnecessary information. Each additional unit of information in an interface competes with the relevant units of information and diminishes the relative visibility of those units.

•  Assisting Users in overcoming errors: Providing error messages that are informative and that teach users how to recover from errors can help them understand the error.

• Documentation and assistance: Documentation and help are important components of the user experience. Provide relevant information that will help your users to accomplish their goal and anticipate when they will need help.

Mind Mapping

The goal of mind-mapping was to organise information visually and to understand the relation between different aspects of the product. During the prototyping process, mind mapping was beneficial to organise and relate the features that needed to be prioritised.

User Flow Diagram

A user flow diagram, or sometimes called a task flow, describes how people navigate through and make decisions about an idea, feature, or product. This enables us to understand all the screens and states that need to be designed and considered throughout the process.

User stories to understand functionality

User stories are concise and easy-to-understand statements that define a common purpose for creating a successful digital product. The primary focus when writing a user story is conveying the user’s needs and what they want to accomplish when engaging in a digital experience. Since user stories are a way to define the user’s needs, the goal is to provide user-focused solutions.

Low Fidelity Paper prototyping

Speaking directly with those you're designing for is the only way to understand their hopes, desires, and aspirations. Majority of the data collection and info validation for this project has been conducted via interviews. In order to facilitate open-ended discussions, the interviews were semi-structured. In total, ten participants were interviewed, and the data was transcribed to draw conclusions, and these participants were contacted again as part of the research for further discussion and testing. Commonly, experts such as speech-language therapists, paediatricians, psychiatrists, clinical psychologists and educational psychologists were involved.

Medium Fidelity Wireframe Designing

Wireframes of medium fidelity were made before designing in Figma. By visualising the actual wireframe, productivity can be increased. Immediately after sketching low fidelity paper prototypes, started designing wireframes in figma. All low-fidelity designs were transferred to figma digitally. Following the design of the basic wireframe, some tweaks and changes were made to the digital wireframe.

High Fidelity Prototyping

After finalising the wireframe, the next step was to develop the visual design. In order to maintain simplicity while adhering to the usability heuristics of interface design, the app was designed to be as intuitive as possible. Google Material Design guidelines were adopted for the app's visual design to make it more recognisable and consistent. Having a consistent visual language was done to ensure consistency in the typography, icon design, and other visual aspects of the application.

The high fidelity design process highlights some key points:

• To get some design inspiration from the latest trends, tested different contrast palettes and dark-mode variants for the initial design.

• Considering that it is designed for used car trading, you cannot expect users to upload visually appealing images without backgrounds. Had to ditch the trendy car listings in the next iteration in favour of a minimalistic design.

• Interfaces should not contain information which is irrelevant or rarely needed. Every extra unit of information in an interface competes with the relevant units of information and diminishes their relative visibility.

• Created a master component project and added the components reusable throughout the project. The master component approach saved some time, and increased productivity during the design process.

• In the first version, the app was called Eurocar, but in the next version, it was renamed Evee (Electronic vehicle), which made more sense to its functionality. The application was rebranded to Carge (Cars that Charge, Car+Charge) in its final iteration.


The prototyping and design phases were iterative, and features were added or removed based on feedback, as well as on preliminary research. Expertise associated with electric cars based on the research and survey, coupled with a vision of what the future holds for the growing electric car industry was acquired. 

It is strongly believed that this product has great potential in upcoming projects that aim to completely electrify transportation. Carge has a more futuristic approach, so it could be improved in terms of aesthetics and functionality for a more modern experience. The electric car industry is still in its infancy and therefore, there are many obstacles to understanding the future market for electric cars. Even the survey statistics reveal that none of the participants owns an electric car. It was planned that the interface would reflect the trending UI styles, but things didn't go as planned and the interface could not be designed aesthetically with stunning images of cars, since we have to expect low quality images taken by users with their phones.